Methods for producing three-dimensional components have been known for some time.
For example, a method for producing three-dimensional objects from computer data is described in the European patent specification EP 0 431 924 B1. In this method, a particulate material is deposited in a thin layer onto a platform, and a binder material is selectively printed on the particulate material, using a print head. The particle area onto which the binder is printed sticks together and solidifies under the influence of the binder and, if necessary, an additional hardener. The platform is then lowered by a distance of one layer thickness into a build cylinder and provided with a new layer of particulate material, which is also printed as described above. These steps are repeated until a certain, desired height of the object is achieved. A three-dimensional object is thereby produced from the printed and solidified areas.
After it is completed, this object produced from solidified particulate material is embedded in loose particulate material and is subsequently removed therefrom. This is done, for example, using an extractor. This leaves the desired objects, from which the remaining power is removed, for example by brushing.
Other powder-supported rapid prototyping processes work in a similar manner, for example selective laser sintering or electron beam sintering, in which a loose particulate material is also deposited in layers and selectively solidified with the aid of a controlled physical radiation source.
All these methods are referred to collectively below as “three-dimensional printing method” or “3D printing method”.
In all of these three-dimensional printing methods, the loose, unsolidified particulate material supports the structural body during and after construction of the structural body. However, additional support structures, which are necessary, for example, in a different layering method (the so-called stereolithographic method), are usually not required in the 3D printing method.
This characteristic has so far been regarded as a great advantage of the 3D printing method, since manual post-processing of the components is not required in order to remove any support structures.
However, if a method such as powder-supported rapid prototyping is used in order to produce a larger number of objects, a variety of problems may potentially arise.
After they are completed, the parts are entirely covered by loose particulate material and are therefore initially not visible to the operator. If the operator uses an extractor to remove the loose particulate material, the produced objects are in danger of being damaged by the suction nozzle. In the case of small parts, in particular, the parts are also in danger of being unintentionally drawn into the suction nozzle.
Large, filigree structures may also be damaged after production when they are removed from the powder bed, if parts of the object are still located in the powder bed and are somewhat more difficult to remove.
It is also possible for components to become dislodged and slip or collapse under their own weight if the loose particulate material beneath the component is carelessly removed.
For all of these reasons, it has not yet been possible to automate the removal of the components from the powder bed.